Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Jason Bright, Glowing Prophet

Whenever a Zombie or Mutant you control dies, if its power was different from its base power, draw a card.
Come Fly With Me — {2}, Sacrifice a creature: Put a +1/+1 counter on target creature you control. It gains flying until end of turn.

Witty Roastmaster

Alliance — Whenever another creature you control enters, Witty Roastmaster deals 1 damage to each opponent.

Cloudstone Curio

Whenever a nonartifact permanent you control enters, you may return another permanent you control that shares a permanent type with it to its owner's hand.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Geralf, the Fleshwright

Whenever you cast a spell during your turn other than your first spell that turn, create a 2/2 blue and black Zombie Rogue creature token.
Whenever a Zombie you control enters, put a +1/+1 counter on it for each other Zombie that entered the battlefield under your control this turn.

Sol Ring

Rooftop Storm

You may pay {0} rather than pay the mana cost for Zombie creature spells you cast.

Empty the Laboratory

Sacrifice X Zombies, then reveal cards from the top of your library until you reveal a number of Zombie creature cards equal to the number of Zombies sacrificed this way. Put those cards onto the battlefield and the rest on the bottom of your library in a random order.

Purphoros, God of the Forge

Indestructible
As long as your devotion to red is less than five, Purphoros isn't a creature.
Whenever another creature you control enters, Purphoros deals 2 damage to each opponent.
{2}{R}: Creatures you control get +1/+0 until end of turn.

Necroduality

Whenever a nontoken Zombie you control enters, create a token that's a copy of that creature.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Hordewing Skaab

Flying
Other Zombies you control have flying.
Whenever one or more Zombies you control deal combat damage to one or more of your opponents, you may draw cards equal to the number of opponents dealt damage this way. If you do, discard that many cards.